Back brace



FIG. 1 is a lower perspective view of a back brace, showing our newdesign;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is a left side elevation view of the back brace in FIG. 1.

The broken lines shown herein are for illustrative purposes only andform no part of the claimed design. The right side elevation view forthe embodiment of the back brace shown in FIG. 1 is a mirror image ofthe left side elevation view in FIG. 5.

The ornamental design for a back brace, as shown and described.